This invention relates in general to door closing devices and deals more particularly with an improved door closer assembly of the type which includes a door closer and an articulated closer arm assembly. A typical door closer of the aforedescribed general type is connected between a door and its frame to exert closing force on the door when the door is released in an open position.
The present invention is particularly concerned with improvements in a door closer of the aforedescribed general type which includes a back check mechanism of an intensity responsive type for controlling movement of a door as it approaches a fully opened position. Such a device operates in response to the intensity of fluid pressure within a door closer and is generally effective to control an attempt to violently or abusively open a door in a manner which could cause injury to a person in the path of the door or result in damage to the door itself and/or its supporting structure
A substantial change in ambient temperature which causes a corresponding change in the viscosity of fluid within the door closer can substantially alter the operational characteristics of a door closer. A back check device of the type hereinbefore discussed has the advantage of being generally temperature responsive. A properly designed intensity responsive back check device can be adjusted to substantially overcome this problem.
Although such a back check device affords substantial advantage it has the disadvantages of being intensity responsive throughout its entire adjustable range of operation. Thus, the device tends to offer a somewhat greater resistance force to the normal opening of a door than might otherwise be desired. The present invention is concerned with this problem.